Aircraft door lock



y 5 J. E. HOGAN 2,833,58

AIRCRAFT DOOR LOCK Filed Aug. 22,1955 R 4 Sheets-Sheet 1 www M y 1958 1E. HOGAN AIRCRAFT DOOR LOCK 4 Sheets-Sheet 2 Filed Aug. 22, 1955lNV/VTOR. Job (5 l/yon y 1958 J. E. HOGAN 2,833,580

AIRCRAFT DOOR LOCK Filed Aug. 22, 1955 4 Sheets-Sheet s y 6, 1958 J.HOGAN 2,833,580

' AIRCRAFT DOOR LOCK Filed Aug. 22, 1955 4 Sheets-Sheet 4 United StatesPatent AIRCRAFT. DooR LOCK John E; Hogan, Los Angeles, Califi, assignorto Northrop Aircraft, 1116;, Hawthorne, Calif., a corporation ofCalifornia Application August 22, 1955, Serial No. 529,662"

1 Claim. (Cl. 292-302 This invention relatesrto' latches, and;. moreparticularly, to a door latch especially suited for locking externaldoors or" panels in a closed positionon the' sur face of an airplane.

The instant invention is considered to be an improvement on the devicebearing Patent No. 2,661,975 issued December 8, 1953 to Harold E.Michael and assigned to Northrop Aircraft, Inc.

The requirements for a suitable aircraft door lock differ substantiallyfrom those of ordinary locks and latches in common use elsewhere. Speedand accuracy of operation, resistance toloads from many directions, andpositive locking action during normal vibration and operating;conditions are the main requirements to besatisfied.

Accordingly, the objects of the present invention include providing anaircraft door lock-which-will'. always be. aligned or will alignitselfwith the matingdoori parts to. assureclosing in, the properposition, providing .a lock which will pull the door in place againstpressureof sealing strips and the like, and which will positivelyseparate .the door from its mating structure when..un-

locked, providing a lock which will carry loads-from allvdirections,.which will have. no. load which tends to provide anunlocking force, and which may be easily operated in gangs'of two ormore from a remote position;

Another object of this invention is' to provide aniair- 2,833,580Patented May 6, 1958 2 cam surface to engage the end of the striker toforce it from the bolt duringthe unlocking operation; Each lock assemblyis normally held in both a locked and a prelatched position by twosprings, balls, and ball" detentsr When locked, the loads on the tongueand striker are purely in shearing directions, thus precluding anyforcewhich tends to open the lock.

My invention may bemo'rereadil'y understood by reference to theaccompanying drawings, shown by way'of illustration and not limitation,wherein:

Figure l is a perspective view showing an airplane using engine nacelledoors having locks-made according to the present invention.

. Figure 2 is a perspective view showing the right-hand front nacelledoor in a slightly open position, as vie-wed from ahead of and above thedoor. I

Figure 3 is a perspective exploded view showing, on a larger scale thanFigure 2, the lock, striker and bolt arrangement.

Figure 4 is a fragmentary view of the bolt and the striker, showing aprelatched position of the bolt.

Figurev 5 is a view similar .to Figure 4 but showing the bolt andstriker in-the latchedaposition. e Figure 6-is also aview similarto-Figure 4 but showing structure to which the striker is secured formount ing on an aircraft and also showing structure to which theboltisattached for" moving; the latter to and from the various latchingandunlatching'positions:

Figure 7 is a fragmentary, cross-sectional viewwillus trating themannerin which the-spring-loaded ball detent's I engage-thebolt.

Figure-2H5. a top viewof: the bolt. Figure 9 isen-enlarged detail view,'partl-ycut away, showing alock operating means' and prelatchingspring;- .Referring to the various figures for a=detailed descripie vtionof a preferred embodiment ofthis-inventi'on, email" plane 10 hasengine nacelles- '12 on each sideof the fuselage 1,4] equipped ,withquickly. removable nacelle doors, 1-6,. 18, 2t), and 22. The doors swingabout an upper hinge line 24and are lockedclosed against-an -interveningfuselage section providing a=lower edge 26:

craft door lock that has component parts therein that Will-permitmanufacturing of the various structures with a. greater tolerance,provide for an adjustment forvvear It is, therefore, a further object ofthis? invention to provide an aircraft door lock having aprela'tchingposition to hold the door in place until the final lock is accomplished.1 7

Other objects and features of advantage will be noted in thedescription: of specific apparatus-formingca' part of:

this specification, to follow. V V

Briefly, the present invention comprises .a lock member having a boltslidable therethrough, thesetwo partspref=- erably mounted on the hingeddoor. ,A' striker, mounted on the closure structure around thed0or,.enters thelock perpendicularly to the path of the bolt. Locking isaccomplished by a tongue within the bolt'which engages. a

slot through the striker. The. tongue isbeveled on two sides to providea. slidinglever action whenlocking the door and to-accomplishaiprelatching action, .in combination with aspiring-loaded linkvattached to the bolt, to return itto. a partially locked position whenthe striker enters the bolt a given-distance. The bolt-includes anearthe bottom center line: of -the fuselage. 5

They forward right-hand door-.16 is further shown- FigurefZ, as viewedfrom Withinthe nacelle looking aft and outwardly at the inner side; ofthe -door. At

, each end of the door lo, a lockimember 28 is iixed to the door, and abolt30,is-slidable forersand aft -within the lock 28. I Attached to thefuselage 14 are .two strikers 32 positioned to enter the locks 28 whenthe door is closed and be engagedby. the bolts 30- when .thedoor;isloc'ked.

An adjustable actuating-rod'fall is connectedto the inner end ofeachbolt 28, as byrivet 3 6,. these rods 34in turn being connectedrespectively to two bell cranks, which are pivotally' connected to. thedoor 16; at crank pivots 38. The bell cranks 37are mutually.connectedsto;

an opening rod 40 movablecrosswiseof the,door:16. It v is thus seenthat" when the operating. rod.40ispulled-out;- wardly from the fuselage14,. the bell cranks 36 and actuating rods 34 operate to pull both bolts30 toward "the :center of the door.

This releases the. door from-,its locked position as will befurtherdescribedherein. H

As shown in Figures 3 and. 4, each bolt 30 is=rectangu lar inform witha' vacant centrallpo'r'tion, 42 into which the striker-'32 will extend.A tongue 44 is formed within I the bolt, .the tongue pointing toward theadjoiningend;

of the door'16 and having a relatively long bevel-.46 and a blunt tip 48intersecting atthe-tip ofth'e' tongue. I tongue 44nea'r itssuppoited'endjha's a straighfportioh 5'0 parallel'to thesides ofthebolt'30 The tongu bisects the vacant portion 42 and is connectedtoi'the. .olt

' 36 only at the 'HaseSZ; The base 52 or the tongueand a slanting camsurface 54 form partitions from side to side to the lower bevel 46. j

Two ball detents 56 and 58 are located in a fore-andaft line in eachexterior side of the bolt 30, each detent on one side being exactlyopposite a detent on the other side. These detents aid in establishingprelatched and locked positions of the door, and will be referred tolater.

The lock 28 (Figures 2 and 3 is fixed to the door 16 by means of twomounting bolts 60 in sheet metal brackets 62 fixed to the door, andcontains a rectangular opening 64 through which the bolt 30 slides. Onopposite sides of the opening 64, and adjacent to thepath of the balldetents 56and'58 of the bolt 30, two threaded holes are provided in thelock 28, and a steel ball 66, spring 68, and retainer. 70.are installedin these holes to press the balls against the sides of the bolt 30 andinto the detents. i

Formed in the end of lock 28 facing the striker 32 on the fuselage 141isa receiving bore 72 having a uniform diameter. Adjacent the receivingbore 72 is a larger opening, 74 also having a uniformdiameterthroughout. Due to the fact that opening 74 is larger than the bore 72there is a shoulder 76 formed between the two openings. Theopening74vhas adjacent thereto and formed in the. lock a taperedmouthentrance 78. The receiving anemone 4 purpose the securing of the strikerto the fuselage 14. The yoke 96 is retained on the striker 32 by washer98 and nut 100.

A suitable operating mechanism for these door locks is shown in Figures2 and 9. The operating rod 40 is rotatably connected to a handle socketmember 102 pivotally mounted on an axis bolt 104 just inside a cut-out106 in the outer skin 108 of the door 16. Socket memher 102 is mountedbetween two side plates 110 riveted to bore 72 mateswith the striker 3,2as the door is being 7 closed. r

As further shown iniFigures 2'and 4, each striker 32 carries a taperednose80which first contacts the entrance 78, thus assuring alignment ofthelocking parts each time the door .16 isclosedgby positioning the doorto an exact location in a plane normal to the striker center-line. Thus,any play at the door hinge line 24 or swaying of the open edge of therelatively large door 16, will not inhibit proper mating of the lockingparts whenever the door is pushed closed. Although the receiving bore72, 7

comprises a 18 90 that isfcomplementary in configure tion to' and isreceived in opening 74 when the bolt and striker are in thelatchedposition. As a part ofmember 88 there isintegral with ring 90.another ring 92 having a' bevel thereon that is. complementary to andreceived in the tapered mouth 78. There are. flats 94 on ring 92 forrotating member88on striker 32." i V p The virtues of the configurationof member 88 coupled .with the configuration ofthfe openin'g 74 andmouth 78 isthat great shear loads maybesupported by the door latch; Ithas been determined *through tests that the instant door lock willwithstand 'a tension load of =approximately 12,000 pounds," acompression load of approximately 17,000 poundsgand shear load ofapproximately 9,000 pounds. 1

When locked, the loads; onthe tongue 44 and striker 32 are purelylinshearing directions as previously stated. Ats a 'result it is importantthat thedoor lock 28 be capable of withstanding suchshear loads asmay beapplied.

channel sections 112 forming a part of the door structure, to strengthenthe installation. A recess 114 is provided in the outer side or bottomof the handle socket memher 102 whereby a lever 116 or the like may beinserted to rotate the socket member 102 and control the operating rod40. The socket member 102 is held in the door locked" position withsmall spring-loaded balls 118 and detents between the socket and sideplates 110 similar to the ball and detent means between the bolt 30 andlock 28. The socket member 102 in this specific embodiment is a, castinghaving a thin outer element 120 integral there with for manually pushinginwardly to unlock the door.

Between the locked and completely unlocked positions of the linkagecomponents heretofore described, a prelatched position is provided, anda latching spring 122 on the operating rod returns the linkage to theprelatched position from the unlocked position. The latching spring 122'is mounted between two slidable washers 124 and 126 which bear againsttwo collars 128 and 130. on the respective outer sides thereof. Collars128 and 130 are secured to operating rod 40. When the rod 40 is .pulledto the unlocked position, one washer 124 bears against a spring stop 132attached to the door 16" while its receptive collar 128 passes onthrough the stop 132, thuscompressing the spring 122. When the operatingrod 40' is thenreleased, the latching spring 122 urges the linkagemembers and the bolt 30 back to the prelatched position as determined bythe spring location.

At each of the bolts 30, the first detents 56 are occupied by the balls66" at the prelatched position, thus affording additional means forproperly determining this position.v 'The second detents 58 in the bolt30 are oo- 1 cupied by the balls 66 at the locked position,simultaneouslywiththe ball and detent assembly at the handle socketmember 102.

In any bolt position, the upper edge of the tongue 44, which is flushwith the top of the bolt 30, can bear against the outer side of therectangular. opening 64 in the lock 28 and thus-transmit door loadsdirectly to the lock 28, so thatthe tongue44 may not be required to takeexcessive ibending loads. Since the striker 32 is also surrounded by thelock bore 72, it is easily seen that the, present lock holds the doorfixed against all loads in every direction, particularly shear loads.Because of the parallel portion 50 on the tongue 44, on which thestriker 32 bears when locked, no load components actin adirection tounlock the door.

To unlock and open the door, the bolt 30 is with drawn fromthe striker32 by rotating the handle socket member 102', and in the. event of thedoor tending to stick closed, the cam surface 54 bears against the endof the striker nose 80 to force separation of the parts and opening ofthe door 16.

As shown herein, the door 16 has two locks, both operable. by a singlehandle or lever. However, it is obvious that a single'lock can similarlybe operated, or

' thatthree or more locks can also be gang-operated by Additionally, themember as may be adjusted on striker" 32 to permit greater tolerance inthe manufacturing of the tongue 44 and other component parts. Further,the memalso provides for adjustment for wearing which maycocur onapplications where. there is a highvibra tionfactor.

Slidable on striker 32 is a yoke that has for its adding other actuatingrods. For ease of operation and protection of moving parts, the bolt 30and the projecting end portion of the striker 32 are preferably given agraphite coating to reduce the sliding friction.

Thus, it is seen that the door locking device of the present inventionis very easily, simply, and quickly operated, which makes it especiallysuitable for aircraft installations .requiringa minimum of maintenancetime.

It is also inherently accurate in its locating and locking positions,and is durable from the standpoint of wear and load-bearing strength.

From the above description it will be apparent that there is thusprovided a device of the character described possessing the particularfeatures of advantage before enumerated as desirable, but whichobviously is susceptible of modification in its form, proportions,detail construction and arrangement of parts without departing from theprincipal involved or sacrificing any of its advantages.

While in order to comply with the statute, the invention has beendescribed in language more or less specific as to structural features,it is to be understood that the invention is not limited to the specificfeatures shown, but that the means and construction herein disclosedcomprise the preferred form of several modes of putting the inventioninto effect, and the invention is, therefore, claimed in any of itsforms or modifications within the legitimate and valid scope of theappended claim.

What is claimed is:

A lock for fastening two parts together comprising a receiving memberattached to one of said parts and having a receiving passage axiallyfacing the other of said parts; said passage being a pair of concentricopenings having a shoulder therebetween; a bolt member slidable throughsaid receiving member in a direction perpendicular to the central axisof said passage; a striker member fixed to said other part opposite saidreceiving member and having thereon structure that is complementary tothe configuration of said passage and is adapted to project into saidpassage when said parts are brought together; said striker having anelongated hole extending therethrough parallel to the sliding directionof said bolt in said receiving member; a tongue movable with said boltlocated to enter and fill said elongated hole when said striker hasentered said receiving membet, to thus determine a locked position;operating means connected to slide said bolt to and from said lockedposition; a first sloping side on said tongue positioned to contact theoutermost end of said elongated hole remote from said other part as saidbolt is being moved.

toward said locked position, to pull said parts together by sliding camaction of said first sloping side against said elongated hole end; asecond sloping side on said tongue intersecting said first sloping sideat the tip of said tongue; said striker having a tapered nose positionedto guide said receiving member into alignmentaround said striker fromoff-center positions during closure of said parts; said second slopingside having a predetermined angle to meet said tapered nose along asloping surface intersection; said bolt and tongue having a prelatchedposition where said tongue tip lies in interference with said taperednose when said parts are being closed; and elastic means connected tourge said bolt and tongue to said prelatched position from an unlockedposition where said tongue and striker do not interfere in passing,whereby said interference during preliminary closure causes said tongueto move against said elastic means until said tongue tip is oppositesaid elongated hole and then said tongue tip will engage in saidelongated hole in said prelatched position to hold said parts adjacentprior to locking by said sliding cam action.

References Cited in the file of this patent UNITED STATES PATENTS

